This nonprovisional application claims priority under 35 U.S.C. xc2xa7 119(a) on Patent Application No. 2001-105335 filed in Japan on Apr. 4, 2001, the entirety of which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a rear suspension attachment structure for a motorcycle, and more particularly to a rear suspension attachment structure providing increasing degrees of freedom of design shape, dimension, an attachment position or the like of a contiguous part. The present invention narrows an interval of an attachment portion while maintaining a stroke amount of a shock absorbing member and concentrating parts at an end portion of the shock absorbing member.
2. Description of the Background Art
FIG. 10 is a side view of a vehicle of the background art incorporating a conventional rear suspension attachment structure. In FIG. 10, a vehicle 100 having a conventional rear suspension 103, a power unit 102 constituted by an engine and a transmission attached to a lower portion of a vehicle body frame 101 of the vehicle 100 is shown. The rear suspension 103 is arranged at rear portions of the vehicle body frame 101 and the power unit 102.
The rear suspension 103 includes a swing arm 104 swingably attached to the rear portion of the power unit 102, a rear wheel 105 attached to a rear end of the swing arm 104, and one end of a shock absorber 106 attached to the rear portion of the vehicle body frame 101. A first link member 107 is attached to the swing arm 104 and is connected to other end of the shock absorber 106, and a second link member 108 attached to the power unit 102 is connected to the first link member 107. The vehicle 100 also includes a head pipe 111 attached to a front end of the vehicle body frame 101, a front fork 112 rotatably attached to the head pipe 111 and a front wheel 113.
The shock absorber or shock absorbing member 106 includes a first attachment portion 116 provided at an end portion of a cylinder portion 115 to the vehicle body frame 101 and a second attachment portion 117 provided at an other end thereof to the first link member 107. The shock absorber 107 includes a stroke amount that effects the length of an interval L1, e.g., an interval L1 between the first attachment portion 116 and the second attachment portion 117 of the shock absorber 106. When a necessary amount of stroke of the shock absorber 106 effecting influence on running performance and ride quality of the vehicle 100 is enlarged, e.g. the interval L1 is increased, a position of the first attachment portion 116 is ultimately raised to a position higher with respect to the vehicle frame.
Accordingly, shapes and attachment positions of a seat, a fuel tank and the like arranged on an upper side of the vehicle frame are undesirably restricted. Alternatively, a position of the second attachment portion 117 is lowered and lengths and attachment positions of the first and the second link members 107 and 108 arranged on a lower side are also restricted. Further, it is difficult to arrange other parts in positions surrounding the first and the second attachment portions 116 and 117 of the shock absorber 106.
The present invention overcomes the shortcomings associated with the background art and achieves other advantages not realized by the background art.
An aspect of the present invention is to provide a rear suspension attachment structure that narrows an interval between attachment positions for a rear shock absorber or shock absorber.
An aspect of the present invention is to increase the degree of freedom of vehicle frame and rear suspension design with respect to shape, dimension, an attachment position or the like of part(s) contiguous to an end portion of the rear shock absorber and rear suspension of a vehicle such as a motorcycle.
These and other aspects of the present invention are accomplished by a rear suspension attachment structure for a motorcycle having a vehicle body, the vehicle body including a rear wheel and a power unit, the rear suspension attachment structure comprising a swing arm having first end and a second end, the first end being swingably attached to a pivotal shaft provided on the vehicle body and the second end being attached to the rear wheel; a shock absorber having a cylinder and a lower end, the cylinder including a side face, the lower end of the rear shock absorber being connected to the side of the vehicle body; and an attachment member, the side face of the cylinder of the rear shock absorber being attached to the swing arm via the attachment member.
These and other aspects of the present invention are accomplished by a rear suspension attachment structure for a vehicle comprising a swing arm, said swing arm having a generally trapezoidal shape with a middle portion, a first swing arm end and a second swing arm end; a rear shock absorber having an upper end and a lower end; at least one upper bracket for said swing arm, said upper end of said rear shock absorber being attached to the middle portion of the swing arm at said at least one upper bracket; at least one lower bracket for said swing arm; and a link mechanism being attached to said swing arm by said at least one lower bracket.
According to a rear suspension attachment structure of the present invention, one end of a swing arm is swingably attached to a pivotal shaft provided on a side of a vehicle body and a rear wheel is attached to other end of the swing arm. A side face of a cylinder of a rear shock absorber is attached to the swing arm via an attachment member and a lower end of the rear shock absorber is connected to the side of the vehicle body. Accordingly, an interval between an attachment portion of the rear shock absorber on a side of the swing arm and an attachment portion thereof on a side of the vehicle body when the rear shock absorber is attached between the swing arm and side of the vehicle body can be reduced. A new space can also be formed at an area surrounding an end portion of the rear shock absorber.
Therefore, the degrees of freedom of shape, dimension and attachment positions of contiguous parts to the end portion of the rear shock absorber can be desirably increased. Further, additional/alternative parts can be arranged at the area surrounding the end portion of the rear shock absorber 34.
A male screw can be formed at the side face of the cylinder and coupled with a female screw portion formed at the attachment member. Accordingly, by rotating the cylinder, the cylinder can be moved in a direction of the extension of a cylinder axis relative to the attachment member. An interval between the attachment portion of the rear cushion on the side of the swing arm and the attachment portion of the rear cushion on the side of the vehicle body can be changed and a position on the side of the vehicle body can be moved upwardly and downwardly as desired.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.